The money is intended to give NHS nurses in England access to the latest technology and ensure cancer patients get advanced radiotherapy treatment.
Health Secretary Jeremy Hunt said most nurses and midwives wanted to “spend time caring for patients.”
The government’s NHS reforms have prompted controversy in the last year.
During a visit to the John Radcliffe hospital in Oxford, ahead of the start of the Conservative party conference in Birmingham, Mr Cameron said £100m will be used to ensure “brilliant” nurses and midwives can get access to the latest software and other devices so they can spend “even more time at the bedside”.
“We’re only able to do this because we’re the only party, the only people, who said ‘whatever else we have to do, whatever other cuts we have to make, we are not cutting the NHS budget, we’re increasing it’.
“That was my pledge, that’s what we are doing,” he added.
A further £40m will be available to help ward sisters and community team leaders develop their leadership skills, with training for 1,000 staff this year.
Mr Hunt, who succeeded Andrew Lansley as health secretary in a recent reshuffle, said: “Most nurses and midwives chose their profession because they wanted to spend time caring for patients, not filling out paperwork. New technology can make that happen.
“That’s better for nurses and patients too, who will get swifter information and more face-to-face time with NHS staff.”
The money will initially be made available in the form of loans, although hospitals will only have to pay back a proportion depending on how well they perform.
The prime minister also announced a £15m cancer radiotherapy innovation fund, with a guarantee that from next April all cancer patients in England will get the most innovative radiotherapy where it is appropriate and cost-effective.
Conservatives are assembling in Birmingham for their party conference.